With the development of information industry, presentation software executed by a computer is a common tool for facilitating expression of ideas or facts for a variety of purposes at a variety of places. Generally, the computer installed with the presentation software is connected to a projector to enlarge the picture to be shown in front of the audience. The speaker then manipulates the execution of the presentation software to play presentation contents and associated operations, e.g. turning pages, moving cursor, highlighting paragraphs, etc., with an input device such as a mouse device.
Nowadays, the use of portable computers or tablets in lieu of a projector for presentation is getting more and more popular. For example, in classes, the students or audience store the presentation file in their computers or tablets, and follow the instructions of the teacher or speaker to operate the presentation file while the teacher or speaker is making presentation with the presentation file.
In general, it is hard to have each of the audience precisely follow the instructions of the speaker to operate the presentation file, and it is difficult for the speaker to know if the audience have synchronized the frames shown on their computer screens with the page being explained. This would limit the effect of the presentation.